Briquette and process for making the same



Patented May 31, 1932 UNITED STATES PATENT OFFICE GUSTAV ROMA-EEK, OF CHICAGO, ILLINOIS, ASSIGNOBTO BERWIND'FUEL COMPANY OI DELAWARE, OI CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE BRIQ 'UE'ITE AND PROCESS FOR MAKING SAME Ho Drawing.

The present invention relates to fuel briquettes and has for its object to rovide a brlquette which will be substantlally dust proof and also of improved character for June 20, 1929, wherein is set forth a briquette and method of forming same employing a 10 deliquescent material either added to the mixture of carbonaceous material and binderbefore manufacture in the briquetting machine or the deliquescent material in solution or dry form is applied to the surface of the prepared 1- briquette, in each case so that it would be free to exert its active hygroscopic properties.

This invention contemplates the applica-v tion to the surface of the briquette of a solution of a deliquescent material, also means for causing the material to adhere, and means for protecting the surface of the briquette against abrasion and dusting.

With certain types of briquette material it is not practical to add the deliquescent material to the mass before the briquette is shaped and in othericases it is not always possible to effectively apply the deliquescent coating to the surface of the prepared-bri- 'quette without some additional treatment.

These difliculties are usually traceable to the binder employed or to the smooth or greasy nature of the surface of the briquette, making it difficult for a solution to be effectively applied.

Wherever such objections are found, the

present invention is applicable, and it comprises the use of heat in impregnating the surface of the briquette with the solution of dehquescent material, the heat being employed by heating the briquette itself, or the solution, or both. The heat will cause the deliquescent material to adhere to the surface for a. considerable period of time and exert its hygroscopic action to sarily so, and may consist of sulphite H3111 are piled, they do not produce a conglomerate heated deliquescent solution or mixture w1t either the deliquescent solution alone or m prevent dusting. In addition tothe hygroscopic material I have Application filed December 2, 1929. Serial No. 411,209.

also found it desirable in some cases to apply therewith a film forming material which will serve to retain the deliquescent material 1n the briquette, add strength to the surface of the briquette and additionally minimize dusting due to abrasion. The film forming material will act as a binder and also provide a protective envelope about the briquette.

The deliquescent material which I propose to employ in solution comprises one or more of a series including calcium chloride, magnesium chloride, and potassium carbonate. The film formingmaterial may also be deliquescent in its nature, although not necesor some other suitable bindercapable of ing to form a smooth, firm envelope. y strong and firm is meant a filmwhich is not excessively sticky so that when the briquettes which "would interfere with handling them. In other words, the coating obtained is but slightly moist or tacky, and can best be described as substantially dry, i. e., relatively dry as compared with a thick sticky mass'of an adhesive-and deliquescent material indiscriminately mixed and applied. Such a covering would not be abrasion resistant nor have a firm, strong surface.

It is, moreover, an object of my invention to provide a briquette having its surface impregnated with the above mentioned materials andwherein this impregnation may be materially assisted by the step of applying thfi 80 film forming agent to the briquette, preferably while the latter is also in heated condition.

With this method of procedure employing combination with the film forming agent, and with or without the use of heat, there results a strong firm surface which will-be hygroscopic and prevent or minimize the effects of abrasion on the surface of the briquettes. In 90 this manner there is overcome the objections to dust formation which occur in the conventional methods of manufacturin and handling of briquettes. The strong nrm surface of the briquette of this invention is slightly moist or tacky, but is relatively dry in that the bri uettes will not be covered with a heavy stic coating such as would interfere with their proper handling by forming a conglo1ncrate. Furthermore'such a thick sticky coverin when allowed to dry would cause the sur ace portions of briquettes to be broken ofl'ortorn ofi in handling, and hence produce exposed surface areas which would crumble and break down the entire surface of the bri- 211;8. The substantially dry strong surface effectively protects the briquette against the results of abrasion while at the same time permitting the hygroscopic effect to be ex-- erted. By the alternative processes above re-.

ferred to which utilize heat, the formation of the substantially dry deliquescent abrasion resistant coating is facilitated.

In carrying out this invention the solution may be applied to suitable rolls, such as pressing and orming rolls in contact with which the briquette mass is passed; or the solution may be applied to the walls of the molds of the usual briquetting machine. In fact, any

suitable means for impregnation may be em- I ployed which will coat thoroughly the suraces of each briquette.

As stated, a solution of hygroscopic material is employed, and this may comprise substantially any deliquescent salt of a class of which calcium chloride, magnesium chloride, and potassium carbonate are examples.

The solutions may comprise up to of deliquescent salts depending obviously upon the nature of the briquette and its surface to be treated. Where the deliquescent material is used alone in the treating solution, the solution is preferably raised to boiling temperature and applied in such condition to the surface of a riquette.

However, it is not necessary at all times to have the temperature at boiling, since there are circumstances wherea lower temperature will be satisfactory. I

It will be understood, however, that a high temperature is desirable in order to prevent crystallization of the solution which will take place at atmospheric temperature.

In addition to the hygroscopic material above mentioned, it is often desirable to impart to the briquette a film or coating which will strengthen the surface and minimize the possibility of dusting by providing a clean' smooth surface which'will be unaffected by abrasion in handling. For this pu ose any suitable film forming material may utilized but I prefer a hyopic substance, as, for example, sulphite uor. The sulphite liquor is preferably mixed with the deliquescent solution alreadyreferred to and the mixture is applied as above described.

The effect of adding the film forming agent is to assist in retaining the'deliquescent a nt, increase the stren hof thesurface o the briquette considera ly, and prolong the efiectiveness of the protection against creation of dust, by acting as a'binder and forming an envelop about the briquette.

Moreover, where a mixture of film forming agent and deliquescent material are employed the mixture need not be heated to the relatively high temperature required where the deliquescent salts are used alone.

It is proposed, as will be understood, to apply'a heated solution comprising a mixture of the deliquescent or hygroscopic materials and the film forming agent so as to thoroughly impregnate the briquette.

I have also found in certain cases that an excellent coating orimpregnation is obtained where-the briquette is treated while in heated condition. In other words, the steps mentioned above produce a very excellently pjrotected briquette if they are a plied to the riquette while the latter is in eated condition either instead of heating the solution, or, as preferred, with both the briquette. and solution heated.

The percentages of the solution containing the deliquescent salts and sulphite li uor may vary greatly. For instance, as sta a solution having a percentage of deliquescent salts up to 60% ormore may be used and as the temperature of the solution is maintained at a high point, crystallization of the solution is prevented. To this solution may be added a varying percentage of film forming agent such as sulphite liquor depending on the pro tection desired against dust and also depending on the nature of the coal.

' If, for instance, the briquette surface were such that it would liberate a considerable amount of' fine dust, then the deliquescent solution should contain a high percentage of the sulphite liquor to produce a strong protective film against creation of dust.

Two very effective solutions which have been employed com rise calcium chloride, 30%, and sulphite hquor 5%; and calcium chloride 40% and sulphite liquor 10%. It

- will be understood,however,that the deliquesthan ordinarily necessary with the deliquequescent solution will maintain the briquette surface h groscopic and prevent dust while the sulphite liquor will provide a film of con-.

protection against the creation of dust. As

stated, the addition of the sulphite liquor to the deliquescent salt solution permits of adhesion of the solution to the briquette surface with the solution at a lower temperature scent salt solution alone used.

It will be understood that an impregnation with deliquescent material may be followed in an impregnation of film forming material as separate steps if desired.

It will be understood, also, that instead of heating either of said solution or a mixture thereof, they may be applied without heating to a briquette, the surface of which is raised to a temperature as will permit the solutions to thoroughly adhere thereto.

With respect to the manner of preparing the briquette in order to raise its temperature, it may be stated that while various means for supplying and maintaining the briquette at increased temperature are possible, wefind that such simple expedients as heating with steam, hot water, or direct heat are desirable. The temperature of the briquette to cause proper adhesion and formation of the fihn will be determined by test as the briquette materials will necessarily vary in character as will also thesolutions.

The method of application, as heretofore setforth, comprises passing the briquettes in contact with rolls carrying the solution and a these rolls, of course, may be heated in order to maintain the solution at a proper temperature. Also, the solution may be applied to the molds in which the briquette is formed.

By reason of the invention herein set forth, the thickness of the coating may be readily controlled and 'itis often desirable to provide a relatively thick coating and film where briquettes are not to be used for a considera- .ble period after their manufacture. In such a case, a deliquescent solution of greater specific gravity will be employed in order that protection will remain effective for a fairly long time.

The present invention is effective regardless of the binders employed in manufacturing the briquette, and'as set forth i'n 'my previous application, it is essential that the deliquescent material be applied in sufficient referred to as the film forming agent, I

quantity to permit the due exertion of its hygrosco ic roperties.

In a ditlon to the difiiculties incident to the use of binders, very often the surfaces of the briquette are oily and will not permit of 7 adhesion of a deliquescent solution unless treated in accordance with the present method.

Moreover, the surface of the bri uettes are frequently smooth and shiny and o a greasylike nature, also making it difficult if not impossible, for any liquid solution containing deliquescent salts to adhere to the briquettes. The present invention overcomes all of these objections in that it allows of a deliquescent 8 material being effectively applied to the surface of a briquette as well as a strong film forming agent which will increase the protective action against formation of dust.

In referring to briquettes herein, it will be understood that they may be formed as usual of finely divided carbonaceous material such as anthracite or bituminous coal, coke fines, or petroleum coke. In fact, the invention is applicable to substantially all types of briquettes which have for their principal ingredient finely divided carbonaceous or com- "bustible material.

In addition to the sulphite liquor, herein found such materials as molasses and starch equally satisfactory for this purpose.

Briquettes having treated surfaces in accordance with'the present invention present many important advantages over the untreated conventional briquette. Thus, briquettes with untreated surfaces will educe odors'when fired from an incandescent fuel bed in the furnacebefore the process of shovelling in or replenishing the fuel supply is completed. This is due to the more volatile hydrocarbons contained in the binding materials distilling at comparatively low temperatures. However, the briquette with the treated surface will not educe such odors unno til much higher temperatures are reached which permits completion of replenishing the fuel supply and closing the furnace doors without being aware of such odors The reason for this is found in the moist briquette surfaces which not only retards the distillation of the more volatile hydrocarbons, but

also produces gases readily combustible at lower temperatures. In actual firing tests, it

was shown that while -firing briquettes with untreated surfaces a certain amount of smoke would pass out 'of the furnace. The briquette with thetreated surface would create a flame and burn the smoke at a furnace temperature that was the same on both tests,

but at which no flame appeared when briquettes with the untreated surfaces were fired.

I claim: I 1. A fuel briquette having a heat united deliquescent abrasion resistant coating.

have 95 sistant film or envelope about the briquette.

4. A fuel briquette having an abrasion re-' sistant deliquescent coating united thereto, said coating comprising a deliquescent and film producing materialwhich'forms a substantially dr and strong exposed abrasion resistant an deliquescent'film or envelope about the briquette.

5. A briquette comprising combustible ma: terial and a surface coating comprising a deliquescent salt and sul hite li nor.

6. A briquette comprising com ustible material and a surface coating comprising a deliquescent salt and starch.

7. A briquette comprising combustible material and a surface coating comprising a deliquescent salt and molasses.

8. The rocess of preparing a fuel briquette WhlCh comprises applying a hygroscopic and abrasion resistant coating to the surface of the briquette in the presence of heat and at such a temperature that an abrasion resistant surface skin or envelo will be formed about the briquette having ygroscopic properties.

9. The process of preparing a fuel briquette which comprises heating the briquette surface and applying thereto a coating of a deliquescent material and an abrasion resistant film producing substance.

10. The process of preparing a fuel briquette which comprises applying to the briquette surface a heated solution of a deliquescent material and an abrasion resistant film producing substance.

11-. The process of preparing a fuel briquette which comprises heating the briquette surface and applying thereto a heated solution of a deliquescent material and an abrasion resistant film producing substance.

12. The process of forming a fuel briquette having a deliquescent abrasion resistant coating united thereto which comprises separately applying a deliquescent material and an abrasion resistant film forming substance to the surface of thebriquette to form a strong film or envelope about the bri uette without substantially reducing the de iqueseenceof the coating. I

13. The process of preparing a fuel briquette having a deliquescent abrasion resistant coating united thereto which comin hand.

y GUSTAV KOMABLK.

prises applying a heated solution of ,3. deliquescent salt and sulfite liquor to the surface of a briquette. 

